This project is collaborative research relationship between Dr. Godwin Ogedegbe (PI) and Dr. Ayoade Adedokun of the Lagos State College of Medicine at the Lagos State University Teaching Hospital in Nigeria (the Foreign Collaborator). It is as an extension of NIH grant R01 HL078566. Hypertension (HTN) is a global problem and so is the lack of adherence (ADH) to prescribed blood pressure medications. Several theories, such as the Health Belief Model, and Social Cognitive Model, have been used to explain ADH behavior in hypertensive patients. But, these models do not adequately capture the social and cultural variations in medication ADH among patients, and as such have largely ignored patients' beliefs about their illness. An approach that takes into account patients' beliefs is the Explanatory Models (EM) of illness developed by Kleinman. EMs are based on medical anthropology concepts and they have been used to explain some of the social and cultural factors that influence health behavior in patients with chronic diseases. This FIRCA study will apply the EM framework to evaluate illness representations of HTN and its influence on medication ADH and BP control, among hypertensive patients followed in a primary care practice in Nigeria. The study design combines (1) a qualitative phase involving an ethnographic exploration of the cultural representations of HTN in 70 hypertensive patients; and (2) a quantitative phase, during which the relationship between the elicited EMs of HTN, medication ADH and within-patient change in BP will be evaluated prospectively in another group of 150 patients with uncontrolled HTN (SBP>140 or DBP >90). ADH will be assessed with electronic medication event monitoring system, while within-patient change in BP from baseline to 12 months will be assessed with an automated BP device. Patient assessments will occur at baseline, 6 months and 12months. This study will contribute to the field of cross-cultural medicine and the knowledge gained from this study will be used to develop culturally appropriate treatment plans as well as behavioral and educational interventions targeted at hypertensive patients from diverse cultures.